JPH0336977A - Servo motor acceleration/deceleration control method and device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an acceleration/deceleration control method and apparatus for smoothly accelerating/decelerating a servo motor.

(Background of the Invention) For servo motors used in robots, etc., it is desirable to move the workpiece by smoothly accelerating and decelerating it without applying impact to the workpiece or the mechanical parts that support the workpiece. A linear acceleration/deceleration method that changes the speed command value linearly with respect to time is widely used. This is to keep the acceleration and deceleration constant during acceleration and deceleration, and the speed change with respect to time has a trapezoidal characteristic. However, with this method, the impact when reaching the target speed or target position is large, which results in a large impact being applied to the workpiece and the part that supports the workpiece.If the rigidity of the support part of the workpiece is insufficient, the workpiece The problem arises that it vibrates.

Also known is a curve acceleration/deceleration method in which curve data indicating speed changes during acceleration/deceleration is stored in memory and control is performed to follow this curve data. However, in this case, it is necessary to switch or change the contents of the memory (memory table) each time the conditions of the workpiece, machine parts, etc. change. Therefore, each time a condition is changed, a different memory table must be created and input, resulting in a problem of troublesome handling.

(Objective of the Invention) The present invention was made in view of the above circumstances, and it is easy to respond to changes in conditions of the workpiece or machine parts, and enables smooth acceleration and deceleration without giving a large impact to the workpiece or machine parts. A first object of the present invention is to provide a servo motor acceleration/deceleration control method capable of performing the following.

A second object is to provide an apparatus that can be used directly to carry out this method.

(Structure of the Invention) According to the present invention, the first object is to control a servo motor that controls speed and position while calculating a speed command value in real time based on command values of a target position, target speed, and acceleration/deceleration time. , the acceleration/deceleration time is divided into three zones of increasing, constant, and decreasing acceleration, and in each zone, acceleration/deceleration is performed while calculating a speed command value in real time so that the speed of the ship is constant. This is achieved by a servo motor acceleration/deceleration control device.

The second purpose is to control the speed and position of a servomotor by calculating speed command values in real time based on the target position, target speed, and acceleration/deceleration time command values. input means for inputting the time of each of the three sections where the acceleration increases, remains constant, and decreases, and the constant jerk in the sections where the acceleration increases and decreases; and a speed command for driving at the constant jerk within each section. This is achieved by an acceleration/deceleration control device for a servo motor characterized by comprising an arithmetic device that calculates a value, and a speed control circuit that controls the speed while following the speed command value.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing speed υ, acceleration α, and ship speed β during acceleration and deceleration.

In FIG. 1, reference numeral 10 is a permanent magnet type DC motor, and 12
is a transistor bridge connected in series to this motor 10. Each of the transistor bridges 12 is sequentially turned on at a predetermined phase by a gate signal G output from a gate circuit 14, and the alternating current supplied from an alternating current power source 16 is rectified and guided to the motor 10. motor 10
The rotational speed ■ is detected by a pulse generator (PG) 18, and the speed signal output from this PGI1 is input to a subtracter 20. The speed command value υ is also input to this subtracter 20, and the difference (υ-V) from the actual rotational speed V is determined. The speed control circuit 22 sends a control signal g to the gate circuit 14 to increase or decrease the motor current based on this difference (υ-■).
This gate circuit 14 outputs a gate signal G with a phase corresponding to the control signal g.

Here, the speed command value υ is obtained as follows.

24 is a CPU as a digital arithmetic unit.

This CPU 24 performs predetermined calculations according to the operating program stored in the ROM 26. Further, 28 is an input means, which is composed of a keyboard, but may also be composed of another controller, a personal computer, etc.
In addition to data such as the target position, target speed υ4, and acceleration/deceleration time To, the following data necessary for calculation of acceleration/deceleration is input. That is, acceleration/deceleration time T. A section T where the acceleration α increases, a section T2 where the acceleration is constant, and a section To where the acceleration decreases.
and a constant ship speed β8 in the interval T, ,T,
Input β2. In this example, since the speed patterns during acceleration and deceleration are symmetrical, the acceleration time and deceleration time are both T O (= T I + Tz + Ts),
β2=−β1.

The calculation device 24 calculates the speed υ for one hour t based on the following equation, assuming that the ship accelerates at a constant speed β in the acceleration period Ti.

υ=1αtdt=iβt2=(βt”)/3...
・・・・・・・・・(1) Also, in interval T2, set t= (t-TI), and υ=
(β(Tl)”/3)+αut=υ1+αut
'・・・◆・・・・・・According to (2), the speed command value υ
seek. That is, in this section T2, the ship speed β is zero and increases at a constant acceleration αa.

Furthermore, in section T3, t = (t Tr Tz), υ = (υ1 + α2 ・T2 ) + α 1 - (βt") / 3 = υ2 + αM t - (βt") / 3... (3
) Here, υ2 and υ2 are the reached speeds within the sections T r and T 2, respectively.

In this way, for each interval T,,T,,Ti,(1
) (2) (Calculate and find the speed command value υ in real time using formula 31, and add this speed command value υ to the subtractor 20.
When the speed command value υ is input, the motor 10 accelerates and decelerates following this speed command value υ. Therefore, as shown in FIG. 2, the speed command value υ changes smoothly, and the motor 10 that follows it also receives less impact. Note that the pulse signal of the P G 18 may be input to the CPU 22 and the amount of rotation of the motor 10, that is, the amount of movement of the workpiece, may be determined by integrating the pulse signal.

When changing the acceleration/deceleration pattern, new set values may be input using the keyboard of the input means 28. Input means 2
8, setting values may be input from another computer or the like.

(Effects of the Invention) As described above, the first aspect of the present invention divides the acceleration/deceleration time into three sections in which the acceleration increases, remains constant, and decreases, and the ship accelerates/decelerates at a constant speed in the increasing and decreasing sections. Since speed control is performed so that the boat speed is zero in a certain section, the motor can accelerate and decelerate smoothly, and no large impact is applied to the work or machine parts. In addition, since the speed command value during acceleration/deceleration is calculated in real time, changing the conditions can be done by simply inputting data such as target speed, acceleration/deceleration time, section T, -T, etc., unlike the conventional curved acceleration/deceleration method. Since there is no need to change the memory table as in the above, it becomes easier to respond to changes in conditions.

Further, according to the second invention, an apparatus is obtained that is directly used for carrying out the method of the first invention.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing the speed υ, acceleration α, and ship speed β during acceleration and deceleration. DESCRIPTION OF SYMBOLS 10... Motor, 24... CPU as an arithmetic device, 28... Input means, TI, Ts, Ts... Section, α... Acceleration, β... Vessel speed.

Claims (2)

[Claims] (1) In a servo motor that controls speed and position while calculating a speed command value in real time based on command values of target position, target speed, and acceleration/deceleration time, the acceleration/deceleration time increases, remains constant, or decreases in acceleration. A method for controlling acceleration/deceleration of a servo motor, characterized in that the method is divided into three sections, and in each section, acceleration/deceleration is performed while calculating a speed command value in real time so that the jerk is constant. (2) In a servo motor that controls speed and position while calculating a speed command value in real time based on command values of a target position, target speed, and acceleration/deceleration time, the acceleration within the acceleration/deceleration time increases, remains constant, or Input means for inputting the time of each of the three decreasing sections and the constant jerk in the increasing/decreasing sections of acceleration, and a calculation for calculating an appropriate command value for running at the constant jerk within each section. 1. An acceleration/deceleration control device for a servo motor, comprising: a device; and a speed control circuit that controls the speed while following the speed command value.